Thus for instance, during the biopsy of a tumor, a hollow needle is pushed into the patient in order to take tissue samples of the tumor which can then be analyzed later in a lab. It must be ensured here that the removed sample is part of the non-necrotic tumor mass. The needle must therefore be pushed into the tumor very precisely. A type of needle navigation is therefore needed. The navigation takes place under the supervision of the physician, who observes images of the needle located in the tissue and refers thereto during insertion thereof. Automatic modes of navigation are also conceivable.
The said method for tumor biopsy applies equally to other methods in which a needle is inserted into the patient body, for instance to the so-called vertebroplasty, in which bone cement is introduced into a broken bone, in particular a vertebra.
Previously during the intervention, fluoroscopic images of the needle were overlayed with images taken prior to the intervention. Since only one representation of the needle from one single perspective was previously available, at best two with biplane x-ray systems, the positioning of the needle with the aid of images is not easy for the treating physician.